External versus internal cardioversion for atrial fibrillation: a meta-analysis of randomized controlled trials

Background: Patients with atrial fibrillation (AF) often require rhythm control strategy for amelioration of symptoms. It is unclear if there is any difference between external cardioversion (ECV) and internal cardioversion (ICV) for successful conversion of AF to normal sinus rhythm. Methods: We performed a meta-analysis of published randomized controlled trials (RCTs) evaluating success of cardioversion using ECV versus ICV. Results: In the pooled analysis of 5 RCTS, there was no difference in success of cardioversion using ECV versus ICV (OR 1.69, 95% CI 0.24–11.83, p = 0.6). In the subgroup analysis, there was no difference between ECV and direct electrode ICV (OR 0.41, 95% CI 0.09–1.83, p = 0.24). However, ECV was significantly better compared with ICV using ICD (OR 11.97, 95% CI 1.87–76.73, p = 0.009). Conclusions: There was no difference between ECV versus ICV in effectiveness for termination of AF. Larger well-designed randomized controlled trials are needed to confirm our findings.